The Mesh Potato

What do you call an 802.11bg mesh router with a single FXS port that automatically forms a peer-to-peer network and relays telephone calls without landlines or cell-phone towers? A Mesh Potato, of course.

The Mesh Potato is an 802.11bg mesh router with a single FXS port (Figure
1).
Adjacent Mesh Potatoes automatically form a peer-to-peer network, relaying telephone
calls without landlines or cell-phone towers. The Mesh Potato hardware
and software is open. The power, Ethernet and FXS ports are robust
to developing-world conditions like static, lightning, bad power and
accidental abuse. The Mesh Potato comes in a weatherproof box for outdoor
mounting and costs about the same as any other Wi-Fi router (less than $100).

An analog phone connects to the Mesh Potato via the FXS port.
FXS (Foreign eXchange Station) is a telephone interface that supplies
power, dialtone and generates ringing voltage.
When you make a phone call, your Mesh Potato talks to the potato down the
street,
which talks to the next potato, and eventually to the destination. The
mesh network can be augmented via backbone links and connected to the
rest of the world using VoIP trunks.

Figure 1. The Mesh Potato

This article describes the history of the Mesh Potato Project, including
how it was conceived and its development so far. I also discuss
the Mesh Potato's design and the technical challenges we
have faced.

History

In June 2008, I attended the Village Telco workshop in Cape Town,
South Africa.
The Village Telco (and I quote) is an easy-to-use, scalable,
standards-based, wireless, local, do-it-yourself telephone company
toolkit. Put simply, the idea is that “some guy in a village” can build
a local telephone network and make a sustainable business by charging
a nominal fee for calls to the PSTN (Public Switched Telephone Network) via VoIP trunks.
We were in Cape Town to work out how to build the Village Telco software and hardware.

Steve Song of the Shuttleworth Foundation pulled together a fascinating
team of people from the development, VoIP, mesh networking and business
communities. The team was small (about ten people) and very hands-on
in its outlook and skill sets (Figure 2). The breakfast and dinner conversations
were fascinating—funny stories about broken-down hotels in
some developing countries and sad stories about the poverty of others.

One of the outcomes was the decision to build a little box called the
Mesh Potato. We started out thinking we would use off-the-shelf
hardware, like wireless routers and ATAs. Suddenly, it dawned on us
that we didn't have to accept non-optimal, off-the-shelf hardware.
We had the skills to design and build exactly the
hardware we needed for the project. We also chose to make the
hardware design open, just like the software.

Since then, we have come a long way. Through a series of development
projects funded by the Shuttleworth Foundation, we have designed, debugged
and built about 20 Alpha Mesh Potatoes (Figure 3). The first phone calls over Mesh
Wi-Fi were made in June 2009, almost exactly one year after the project
kicked off. We currently are preparing for a Beta run of Mesh Potatoes,
with full production scheduled for early 2010.

Figure 3. Prototype Mesh Potato (on the Right)

Why Not Mobile Phones?

We keep hearing how popular mobile (cell) phones are in the developing
world. I have seen how well a humble cell-phone works, penetrating to
the corners of some really remote areas of the world. So why do we need
a Wi-Fi-based system like the Village Telco?

The answer is simple. The call costs for mobile phones are very expensive for many
people in the world. In many cases, it's roughly the same cost as a mobile
call in a developed country. If you are earning $1/day, a 50-cent mobile
call is very expensive (Figure 4).

Figure 4. If cell phones could talk!

Although mobile phones have delivered remarkable benefits to developing
countries, the mobile oligopolies that have emerged in the process have
kept call charges artificially high. Worse, mobile operators tend to
function as “walled gardens” in order to entrench their market share.
Just compare the price of an e-mail message on the Internet (zero) and via a cell
phone (20 cents for a text message), and you get some idea of the problem.

Communities in the developing world need an alternative. Hence the
need for the Village Telco—a system that uses commodity Wi-Fi technology
and unlicensed spectrum to provide low-cost phone calls.

Have been installing some Open-Mesh networks in low income areas as well as local small network groups and this combined Mesh CPE and Voip ATA is the best invention I have seen since the Meraki Mini. (or OM1 - lol)

Since the analog signals from the phones are digitized, is there any encryption to at least keep the casual evesdroppers at bay?

Also is there any way that one could buy an unpopulated PC board, any proprietary chips and a parts list for the rest to make one at home? This looks like a really interesting way to establish a small, localized phone system.

Also, IIRC there was an ethernet block on the system diagram. Does that mean this thing could function as an RF LAN/WAN? If that were so secure comm could be handled by encrypting VOIP on a laptop.

This is a very cool device, kudos! I just got to wondering though...what would it be like to use ultrawideband? From what I've read, it's possible to get a lot more data throughput with a lot less power. The FCC doesn't allow it in the U.S. but maybe in the third world that won't be an issue...and it would be nice if they paved the way for us!

Mesh networking for analog phones is a good concept, but to be broadly useful it also needs to support digital communications, with computers or smart phones as the client devices. It would seem what while developing them, you ought to go ahead and enable them for broader uses.

My concern is emergency disaster situations, and here in the U.S., as elsewhere, emergency response will require the conveyance of data as well as voice. I have been involved in some disasters and data communications proved to actually be more important than voice communication. From maps to inventories, logistic control to medical imaging, ground-penetrating radar to biometric identification. The list goes on. We can use CB or handheld shortwave for voice. Data is the main need.